Sol-electrophoretic deposition (SEPD) kinetics and properties of pure and W-doped titania thin films

Highlights: • Studying the SEPD process kinetics using I-t curves. • TiO₂ and W-doped TiO₂ coatings produced by the SEPD process were compared. • Enhancing the photocatalytic degradation efficiency of MO by doping of W into TiO₂ up to the concentration of 3% mol. • 3% W-doped TiO₂ showed the lowest band gap energy. Pure TiO₂ and W-doped TiO₂ coatings were applied on the mild steel in various alcoholic media by sol-electrophoretic deposition (SEPD) process to investigate the kinetics, structural, morphological and photocatalytic properties of these coatings. Results demonstrated that the mobility of particles increased in each suspension via an increase in voltage. FESEM observations illustrated better uniform morphology for coatings obtained in propanol and butanol. The XRD pattern for TiO₂ and W-doped TiO₂ samples revealed that the anatase phase is the main phase in all patterns and there are no characteristic peaks for WO₃, but the FTIR analysis determined the entrance of W in TiO₂ structure. The Efficiency of photocatalytic degradation of methyl orange (MO) solution increased with adding W from 46.4 to 87.9 % for TiO₂ and 3%W-doped TiO₂ samples, respectively. Also, the UV–Vis diffuse reflectance spectroscopy (DRS) results determined 3%W-doped TiO₂ with the lowest band gap energy as the optimal coating.